Ormarion - 30-5-2021 at 07:37
Hello everyone, just wanted to share a synth i tried some time ago: Thialdine
This compound having quite an interesting structure have a very special smell described as shrimps like. After doing some research and with the help
of one of the Illumina chemistry forum admin (called NI2) i have been able to exploit an old german protocol.
The procedure claim to bubble hydrogen sulfide trough acetaldehyde ammonia trimer during 6h wich precipitate huge flaky crystals
I first made some of this trimer by SLOWLY adding acetaldehyde to 30% ammonia wjile keeping the thing under 10°c (this seem to be important as it is
described in different protocoles i found). This need to be done carefully as the reaction is quite exothermic (you can hear popping sound when the
acetaldehyde fall into ammonia).
Once you finished the addition i let it stirr 10 more minutes. At this point the mixture was a syrupy sligtly white/ transparent mixture. I then setup
a H2S generator (iron sulfide and HCl). I put some lead acetate indicator aroud my setup and turned my fume hood on (friendly reminder that H2S is
nasty, please be careful when using it).
I added some ml of excess ammonia in the mixture and started bubbling slowly trough the concentrated solution (around 50ml). The bubble rate was
around 2 to 3 bubble a second using a glass pipette as outlet.
The solution slowly became white and after about one and half an hour the whole mixture precipitated white flaky crystals. I added 50 more ml of water
(dissolved everything back). At this point the solution got a slight bleu/green tint). I continued to bubble for one more hour and got the same
precipitation. As my generator was running out and the night was falling i stopped the reaction and filtered the mixture.
I obtained about 10g or so of white powder wich seemed pretty soluble in water.
Purification in the protocol was achived by dissolving it in 1 part ethanol 3 part water and by letting it evaporate . From my side i tried to recryst
it but the thing turned from transparent to a very bright white solution upon heating so i believe i decomposed some of it. Haven't really recovered
much from it so i would recommend not trying to purify it this way.
Final product got a veeeery potent shrimp sea food smell, even after 1 week of staying air opened the smell in my lab was super strong.
During the H2S bubbling step the smell was already strong but as i never smelled it before and same for ammonium sulfide i wasn't sure at first it was
working
If you have some questions or feedback it will be a pleasure to read you all. I still need to analyse it under IR spectrum, TLC and fusion point.
the pictures are the mixture after bubbling and filtration
[Edited on 30-5-2021 by Ormarion]
clearly_not_atara - 30-5-2021 at 08:17
What an interesting ring. Why does it form stably in these proportions? The world may never know. Nice pictures!
Ormarion - 30-5-2021 at 08:41
Thank you ! That was a very interesting synthesis, but also it stink as hell ^^"
Prepic - 30-5-2021 at 10:41
Fantastic! I love hearing (and seeing a great outline of a procedure to follow) about such strange and unusual chemicals such Thialdine, both in
structure and as you outlined, a overwhelming smell of shrimps/seafood. I also really like the fact that this seems pretty accessible to most of us
amateur chemists here, I think I'm adding this to my to-do list.
Newton2.0 - 30-5-2021 at 15:12
Haha, fingers crossed the container doesn't spontaneously break